Process of producing highly reactive compounds by metathesis



PROCESS OF PRODUCING HIGHLY REACTIVE COMPOUNDS BY METATHESIS Filed Oct.8, 1962 2 Sheets-Sheet 2 March 5, 1968 P. KOLLSMAN 3,372,101

Fig. 3

' IIA VII/I4 INVENTOR. Paul kallsmmz A rraza NF) Uited States Patent3,372,101 PROCESS OF PRGDUQHNG HIGHLY REACTIVE COMPOUNDS BY METATHESISPaul Kollsman, 100 E. 50th St, New York, NY. 10022 Filed Oct. 8, 1962,Ser. No. 228,867 2 Claims. (Cl. 204-180) This invention relates to thetreatment of compounds composed of anionic and cationic constituents forthe purpose of economically upgrading the source materials by producingproduct compounds which are more highly reactive than the compounds fromwhich they are produced.

Compounds which occur plentifully in a natural state are normally stableand substantially non-reactive. Their economic value is correspondinglylow. This invention provides a process for converting stable rawmaterial into less stable and more highly reactive products. Forexample, calcium sulfate and sodium chloride are inexpensive, stablematerials in ample supply. The invention permits conversion of these twosource materials into calcium chloride and sodium sulfate, each of whichis commercially more valuable because of its higher reactivity.

The invention involves treatment in a multicharnber electrodialysis celland resembles in some respects the known process of metathesis. Itdiffers, however, from the known processes in that electrical energymust be expended to force the ions of the source materials into otherchambers to form the products and, further, in that the products, ifleft without the influence of the current-producing direct potential,will revert into the source compound form. In a sense, electrical energyis stored in the products, or the process may be termed an uphill" movement of the ions involved, forcing them to move in a direction in whichin the absence of the applied direct potential and current they wouldnot move.

The critical distinction between ordinary electrometathesis in amultichamber membrane cell and the present process is ascertainable asfollows:

It may be assumed that a conventional metathesis process is beingcarried out in a multimembrane cell by application of a directpotential, resulting in a flow of direct operating current through thecell. It may then be assumed that the operating current is interruptedand that a pair of non-polarizing test electrodes is inserted in thecell, one test electrode in one electrode chamber and the other testelectrode in the other electrode chamber. Then a galvanometer connectedbetween the test electrodes will indicate the flow of a test currentwhich is in the same direction as the operating current.

If a corresponding test were made in connection with the practice of thepresent invention, the direction of the test current would be oppositethe direction of the operating current.

The test electrodes may, as is readily seen, be inserted intointermediate chambers of the cell. One test electrode may be in oneendrnost source compound chamber and the other test electrode may be putin the other endmost source compound chamber. Or the test may be madeacross the minimum unit of cells required for producing a product. Inthat case, one test electrode would be in one source compound chamberwhich is followed by a product chamber, a source compound chamber,another product chamber and another source compound chamber containingthe second electrode. In all these instances the present invention ischaracterized by a reversal of the current direction.

In comparing the properties of the source compounds with those of theproduct compounds produced by the present invention, one or more of thefollowing properties will be noted:

When mixed, the product compounds generally react 3,372,101 PatentedMar. 5, 1968 to revert into the source compounds from which they wereformed.

The sum of the heats of formation of the source compounds is alwayshigher than the sum of the heats of formation of the products producedtherefrom. This appears to be characteristic and indicative of thestorage of electrical energy in the product and of the directionalrelationship of the test current and the operating current abovedescribed.

The products have a higher degree of ionizability than the sourcecompounds. Generally their solubility is also higher. Further, thesource compounds generally have a lower dissociation constant than theproduct compounds.

The source compounds are generally less ionizable than the products,hence the product solutions have relatively a higher conductivity.

A weakly basic source material is convertible into a highly basicproduct, for example ammonium hydroxide into sodium hydroxide.

A weakly acid source material is convertible into a strong acid, forexample acetic acid into hydrochloric acid.

A source material may be highly volatile whereas the products are not.

Thus, volatile solutes may serve as source materials such as solutionsof gases in solvents, for example CO in water or NI-I in water. In thisconnection, the process may be carried out under superatmosphericpressure conditions to maintain greater amounts of gas in solution.

Where the purity of the product is an important factor, it is preferredto operate with ionic concentrations in the source solutions lower thanthose existing in the membrane pores and in the product chambers of theapparatus.

In cases where the product compounds are so highly soluble as to requireno solvent addition to prevent precipitation, the product solutionsconsist preferably entirely of ions and accompanying solvent moved fromthe source liquid chambers through the membranes.

In certain instances it may be necessary to add just enough solvent tothe product chambers to prevent precipitation. Another way of preventingprecipitation is operation at elevated temperatures.

The process is applicable to all compounds capable of dissolving in asolvent and dissociating therein to form an ionized solution. The ionsmay be inorganic, or organic. The solvent may be of inorganic or organicnature.

Polar solvents of high dissociating power and high dielectric constantare preferred. Examples of such solvents are water, acetic acid,alcohols, acetone, ammonium hydroxide, liquid ammonia or carbon dioxide.

The source compounds from which products are formed according to thisinvention are generally solutes, for example NaCl, but the solvent mayor may not enter into the process. When it does, for example by solventdecomposition under polarizing conditions, additional product formingconstituents become available. Thus, for ex- 7 purposes.

Nevertheless, a pure solvent may be employed as a source compound in aspecial arrangement in which the deionizing chamber is of practicallyzero thickness, due, for example, to contact of the bordering membranesas shown in FIG. 4. Alternately the deionizing chamber may contain aspacer of ion exchange material for establishing a continuous solidelectrically conductive bridge between the bordering membranes, as shownin FIG. 3. In either arrangement an electric current is capable ofpassing through such a chamber to which solvent may be supplied from theoutside. Solute ions pass into the deionizing chamber through itsbordering membranes from the neighboring product chambers. Thus, ineffect, solute and solvent are present in the deionization chamber, butsolute and solvent come from different sources, one from the neighboringproduct chambers, the other from an outside source. Both are decomposed,the solvent by operation under polarizing conditions.

In order to illustrate the practice of the invention it may be assumedthat an ample supply of gypsum is available and that it is desired toproduce a commercially more valuable product therefrom.

One may then proceed as follows:

Example A.--The heat of formation of gypsum, CaSO is first determined as335.72 Kcal.

Chemical handbooks contain extensive heat of formation tables listing avast number of compounds and CaSO is readily located therein.

The next step may be the selection of one or two suitable main products.It is evident that one must have a Ca component, the other a $0,component. The heat of formation table serves as a convenient guide andfrom the 50., listings Na SO may be selected. This now points to theneed for a companion source compound comprising a Cl component. Itshould be relatively inexpensive and readily available. For the purposeof the example NaCl is chosen. This fixes the second product compound asNa SO on the basis of the formula A are anionic components C arecationic components A C and A C are source compounds A C and A C areproduct compounds A characteristic of the present inventive process isthat the sum of the heats of formation (HF) of the source compounds mustbe greater than the sum of the heats of formation of the products, thusThe sum of the heats of formation of the source compounds is HF CaSO +HF2 NaCl=335.72+196.72=532.44 Kcal.

The sum of the heats of formation of product compounds is Therequirement of Formula 2 is therefore met.

Particulars of the process are given below.

Following is an excerpt from a table beginning on page 1807 of theHandbook of Chemistry and Physics, 42nd Edition, The Chemical RubberPublishing Co., Cleveland, Ohio. The excerpts are limited to Ca, Na and80., compounds to illustrate the foregoing example.

4 S0 Compounds: HF, Kcal. A12(SO4)3 (NH SO 277.66 NH HSO 240.43 B2180345.28 K 50 338.62 CuSO, 178.7 H 189.75 FesO 217.23 PbSO, 214.6 MgSO301.08 Na SO 326.67 NaI-ISO, 265.19 ZnSO, 229.51

Example B.The following example is again based on CaSO as one of thesource compounds. Ca(NO is chosen as the principal product compound,pointing to the need for a companion source compound yielding N0 KNO ischosen which would make the second product K 80 HF CaSOH-HF 2KNO=335.72+237.56=573.28 Kcal.

for the source compounds.

HF Ca(NO +HF K SO =225.3+338.62

=563.92 Kcal.

for the product compounds.

Formula 2 is again fulfilled. For the purpose of this example the heatof formation table of the aforesaid Handbook of Chemistry and Physicswas again consulted, but no additional excerpt is given, as theprinciple was sufficiently illustrated in Example A.

Example C.Aqueous ammonia NH OH is available as a source compound havinga heat of formation of 87.814 Kcal. Possible products and the requiredcompanion source compound are determinable from the heat of formationtable of which the following is an excerpt.

NH, Compounds: HF NH, acetate 150.25 NH Br 64.708 NH C1 75.08 NH F111.71 (NH CO 223.4 NH NO 87.93 (NI-19 50 277.66

OH Compounds: HF NaOI-I 101.91 KOH 102.01 LiOH 116.4 Ca(OH) 236.1 Mg(OH)223.4 Zn(OH) 158.4

Principal product NH Cl. Second product NaOH. Companion source compoundNaCl.

HF NH OH+HF NaCl=87.814+98.36'=186.174 Kcal.

for the source compounds, and

HF NH cl-l-HF NaOH=75.08+101.91=176.99 Kcal.

for the product compounds. Formula 2 is fulfilled.

Example D.Starting again with NH OH as a source compound, NH NO and NaOHare chosen as products,

NaNO serving as companion source compound.

for the source compounds and HF NH NO +HF NaOH'=87.93+101.91:189.84Kcal.

for the product compounds. Formula 2 is again fulfilled.

In the computation and comparison of the heats of formation the numberof source compounds is always equal to the number of the productcompounds. In a cell having a great number of chambers a sourcecompound,

or a product, is counted as often as it occurs in a chamber. If, forexample, NaCl solution occurs in three deionization chambers, it iscounted three times.

In computing the heats of formation, the heat of formation of thehypothetical product is included which would be formed of the residualanions and cations of the tWo deionization chambers nearest theelectrodes. If the deionization chambers lie adjacent the electrodechambers, then the ions in question are those entering into theelectrode chambers, for example H at the cathode and Cl at the anode.If, on the other hand, deionization takes place in the electrodechambers proper, then the ions forming the hypothetical product arethose ions of the anolyte and catholyte which do not pass into theadjacent product chambers.

FIG. 1 is a diagrammatic elevational view of an electrodialysis cell forpracticing the invention;

FIG. 2 is an end view of the apparatus shown in FIG. 1; and

FIGS. 3 and 4 are diagrammatic illustrations of modified cells.

The cell housing 11 is subdivided into individual chambers by cationmembranes 12 and anion membranes 13 arranged in alternating sequence. Inone terminal chamber a cathode 14 is provided from which a lead 15 leadsto a suitable source of direct current (not shown), and the otherterminal chamber contains an anode 16 with a lead 17. The indicatedpolarity of the electrodes and membranes makes chambers 19, 21, 23, 25,27, and 29 deionization chambers and chambers 20, 22, 24, 26 and 28concentration chambers. Chambers 18 and 30 are electrode chambers.

Each chamber has an inlet port at the bottom and an outlet port at thetop. These ports are unnumbered for the sake of clarity. Means areprovided for circulating the liquid in the individual chambers withinthe chambers at a rate in excess of the inflow and outflow rate. Forthis purpose a bottom circulation port 31 and a top circulating port 32are provided for each chamber connected by a circulating duct 33 (FIG.2) and a pump 34, there being an individual pump 34 and duct 33 for eachchamber. A make-up duct 35 and valve 36 permits addition of liquid toeach concentration chamber.

A second source liquid supply duct 37 is manifolded to deionizationchamber 13, 23 and 27. A first source liquid supply duct 38 ismanifolded to deionization chambers 21, 25 and 29. A further liquidsupply duct 39 is manifolded to concentration chambers 18, 20, 22, 24,26, 28 and 30.

The chambers are 50 mm. wide, 300 mm. high and 3 mm. thick. Themembranes are Nepton membranes CR61 and AR 111A. CR-61 membranes areessentially styrene divinyl benzene copolymer with sulfonic ion exchangegroups, a cation exchange membrane (patent to Clarke 2,731,411). The AR111-A membrane is an anion exchange membrane, is essentially a styrenedivinyl benzene vinyl pyridine membrane.

The electrodes 14, 16 are platinum.

A first outflow duct system 40 manifolded to concentration chambers 20,24 and 28 is provided for the first product and a second outflow ductsystem 41 manifolded to chambers 22 and 26 is provided for withdrawal ofthe second product. Outflow ducts 42 and 43 extend from the electrodechambers. The total liquid capacity of each chamber includingcirculating duct 33 and pump 34 is 300 cc.

Provision is made for conducting cathode chamber eflluent into the anodechamber. A duct 44 extends from duct 42 to the cathode chamber inflowduct 45. Duct 44 is controlled by a valve 46. A further valve 47 permitsclosing of duct 42. Valves 148 are provided in the inflow ducts to theconcentration chambers.

A pair of non-polarizing test electrodes 48, 49 are connected by leads50, 51 comprising a switch 53 to a galvanometer 52. When the switch isclosed a circuit is established between the electrodes and thegalvanometer indicates the direction of the current which, this being acharacteristic of the invention, is opposite the direction of theoperating current flowing between main electrodes 14, 15 through thecell.

The test electrodes 48, 49 are shown in chambers 18 and 30,respectively. The test electrodes need not be spaced thus far apart. Itis s-ufficient to space them three intermediate chambers apart. Thusthey may be installed in chambers 18 and 22, or chambers 22 and 26, forexample.

T est 1.-CaSO was solvated in water to form a saturated solution andNaCl was solvated in water to form a 0.2 N solution. NaCl solution wassupplied to chambers 19, 23 and 27 and CaSO solution was supplied tochambers 21, 25 and 29. All other chambers were originally filled withWater. Circulation rate of pumps 34: 200 cc./ min. Potential 19 volts.

After 30 minutes tests indicated the presence of NaOH in chamber 18;CaCl in chambers 20, 24 and 28; Na SO in chambers 22 and 26 and H 50 inchamber 30.

Operation was continued and the outflowing circulating streams passingthrough ports 32 were adjusted to 0.8 by addition of water at 35, 36prior to reentry of the circulating liquid into the product chamber.

After 48 hours of operation the liquid passing through duct 42 was 0.8 NNaOH, the liquid passing through duct 49 was 0.8 N CaCl the effluent ofduct 41 was 0.8 N Na SO and the outflow through duct 43 was 0.8 N HAfter carrying out the test CaCl solution and NaSO solution were mixedand produced a precipitate of CaSO and a solution of NaCl.

Test 2.-A test was conducted with saturated aqueous CaSO solution as intest 1, and an aqueous 0.18 N KNO solution as the companion sourcesolution. Potential 20 volts. Make-up water was supplied to limit thenormality of the liquid outflow of the concentrating chambers 18, 20,22, 24, 26, 28 and 30 to 0.7 N.

Results: After 48 hours of operation duct 42 yielded 0.7 N KOH, duct 40yielded 0.7 N Ca(NO duct 41 yielded 0.7 N K 80 and duct 43 yielded 0.7 NH 80 The cell was then operated for 48 hours at a temperature of C. withthe inflow of make-up water reduced to produce concentrations of theproduct solution in excess of the normal solubility of the products atroom temperature. Resulting products were: From duct 40: 3.2 N Ca(NOwith a trace of Na SO duct 41: 2.1 N K 50 with a trace of Ca(NOOperation at elevated temperatures is desirable in the commercialpractice of this invention because a product, such as salt, may berecovered in its solid state by cooling of the product solution leavingthe salt depleted cold product solution available for reuse in theprocess.

Test 3.First source solution: 0.4 N NH OH; second source solution: 0.4.NaCl in Water. The cathode chamber effluent (duct 42) was used as anodechamber influent, and the anode chamber efliuent passed through duct 43without the addition of water at chamber 30.

Make-up water was added to chambers 18, 20, 22, 24, 26 and 28 tomaintain a normality of 0.8 N in the outfiows from chambers 20, 22, 24,26, 28 and 30. Potential 17 volts.

After 48 hours of operation: duct 40 yielded 0.8 N NH Cl; duct 41yielded 0.8 N NaOH; duct 43 yielded 0.8 N NaOH.

48 hours after reduction of make-up water inflow to less than one-halfinto chambers 20, 22, 24, 26 and 28, duct 40 yielded 2.6 N NH Cl andduct 41 yielded 2.1 N NaOH.

Test 4.First source solution: aqueous 0.35 N NH OH; second sourcesolution aqueous 0.15 N NaNO Potential 18 volts. Valve 47 closed, valve46 open, duct 45 closed.

After the first 48 hours of operation with addition of make-up water forcathode and product chambers to limit the normality of the outflowingliquids to 0.75 N, duct 42 yielded 0.75 N NaOH; duct 40 yielded 0.75 NNH NO duct 41 yielded 0.75 N NaOH; and duct 43 yielded 0.75 N NaOH.

48 hours after reduction of make-up water inflow into the productchambers to less than one-half, duct 40 yielded 2.65 N NH NO with atrace of Na and OH and duct 41 yielded 2.35 N NaOH with a trace of NH;and N In processing compounds forming ionic solutions of low electricalconductivity, low solubility such as B2150 or compounds having a lowdissociation constant such as acetic acid, H CO or NH OH, or in theprocessing of a variety of weak inorganic or organic acids and bases orweakly dissociated solvents, it is preferred to modify the abovedescribed apparatus by reducing the thickness of the chambers containingliquids of low conductivity to a point where the bordering membranespractically contact except for a thin film of liquid therebetween.Alternatively, electrolytically conductive spacers of ion exchangematerial, preferably of amphoteric nature, may be used through which theliquid flows in a substantially tortuous path. Such spacers may be usedin the deionizing as well as in the concentrating chambers.

Modified cell.-Tortuous path spacers of 3 mm. thickness were installedin all chambers. The spacers were made by molding a mixture of equalquantities of fibers of 0.1 mm. thickness and 1 mm. length, the fibersconsist-- ing of quaternized and of sulfonated polyethylene-styrenecopolymer, respectively, as described in my Patent No. 3,271,292, datedSept. 6, 1966.

Molding took place at 320 F. and 1000 p.s.i. pressure with subsequenthydrolysis in aqueous solutions of 1 N HCl, 1 N NaOH and 1 N NaCl at 160F.

Test .Spacer equipped cell. First source compound: H200 made byabsorption of CO in water to form a saturated solution. The solubilityof CO in water is 0.00145 and the dissociation constant of the resultingH2CO3 lS X 7.

The H CO solution is only weakly conductive.

Second source solution: aqueous 0.1 N NaCl solution. Product compoundsto be formed: Na CO and HCl.

HF Na cO -l-HF 2 HCl:270.56

+79.116:349.676 Kcal.

Catholyte efiluent (42) was conducted through the anode chamber 30.Make-up Water addition to chambers 18, 20, 22, 24, 26 and 28 at a rateto produce a normality of the effluent of 0.6 N. Potential 22 volts.

After 48 hours, duct 40 yielded 0.6 N Hfil; duct 41 yielded 0.6 N Na COand NaHCO and duct 43 yielded 0.6 N Na CO and NaHCO The test wasrepeated at a potential of 36 volts. After 48 hours, duct 40 yielded 0.6N HCl; duct 41 yielded 0.6 N N21 CO andduct 43 yielded 0.6 N Na CO Test6.-Cell with amphoteric membrane spacers in all chambers. First sourceliquid: acetic acid dissolved in water to form a 0.8 N solution. Secondsource liquid: an aqueous 0:1 N solution of NaCl. Dissociation constantof acetic acid 1.76 10 HF acetic acid-i-HF NaCl=117.71-i98.36=216.07Kcal.

HF Na acetate+HF HCl: 171.16

+39.558=2t10.718 Kcal.

Catholyte eflluent 42 was used as anode chamber 30 infiuent. Make-upwater. addition to limit the eflluents to a normality of 1 N.

Potential 21 volts. After 48 hours, duct 40 yielded 1 N 8 H01; duct 41yielded 1 N sodium acetate and duct 43 yielded 1 N sodium acetate.

Test 7.Test 4 was repeated in a cell modified to contain an amphotericmembrane spacer 54 (FIG. 4) in chambers 19, 21, 23, 25, 27 and 29.Potential 16 volts. No addition of make-up water to the productchambers.

After 48 hours of operation, duct 40 yielded 2.9 N NH NO and duct 41yielded 2.55 N NaOH.

The products were of higher concentration and greater purity than thoseobtained in test 4.

Test 8.Test 5 was repeated after saturating the water with CO under 6kg./cm. pressure. The cell was maintained under a pressure of 7 kg./cm.After 48 hours of operation, duct 40 yielded 0.6 N HCl; duct 41 yieldeda mixture of 0.6 N of Na CO and NaHCO and duct 43 yielded an 0.6 Nmixture of Na CO and NaHCO The NaHCO content was higher in relation tothe Na CO content than in test 5.

Test 9.Cell basically as used in test 1 modified to conduct the anodechamber effluent into the cathode chamber. Source compounds: 0.1 Naqueous solution of (CI-1 N-formate and 0.1 N aqueous solution of aceticacid. Anode chamber effiuent was conducted into cathode chamber. Aceticacid solution was supplied through duct 37 into chambers 19, 23' and 28and (CH N-forrnate solution was supplied through duct 38 into chambers21, 25 and 29. Solvent water was supplied to concentration chambers 20,22, 24, 26, 28 and the anode chamber 30 in a quantity sufiicient toproduce an efiluent concentration of 0.3 N. Potential 24 volts.

After 48 hours of operation, eflluent from duct 40: 0.3 N (CH N acetate,and from duct 41 0.3 N formic acid. Duct 42 yielded 0.3 N formic acid.

Test 10.Cell with membrane spacers as used in test 6. Source solutions:acetic acid dissolved in methyl alcohol to form a 0.2 N solution andNaCl dissolved in methyl alcohol to form a saturated solution. Methylalcohol was used as a make-up liquid in a quantity sufiicient to producea product concentration of 0.3 N. Potential 22 volts.

Products: Duct 40 yielded 0.3 N HCl; duct 41 yielded 0.3 N Na acetate;duct 43 yielded 0.3 N Na acetate. It was also found that the HClsolution contained methyl chloride.

Test 1I.For the purpose of this test the manifolds were removed from thecell to maintain separate the several inflows and outflows to and fromthe chamber. The thickness of chambers 21, 25 and 29 was reduced to 0.5

A plurality of source compounds were selected to produce a plurality ofproducts, in excess of two. The sum of the heats offormation of allsource compounds was greater than the sum of the heats of formation ofthe products.

In the latter sum was included the heat of formation of the theoreticalproduct compound formed by the cation of the source compound nearest thecathode and the anions of the source compound nearest the anode.

The process potential was. again reversed with respect to the opencircuit potential existing between the electrode chamber liquids asmeasured by non-polarizing electrodes.

Six source compounds:

2NaClCa OH.) 2KC12 acetic acid -2NaNO CaSO Product compounds to beformed:

CaCl 2KOH2HCl2Na acetate--Ca(NO Hypothetical product compound: Na SOHeats of formation of source compounds:

+335.72=1438.46 Kcal.

Heats of formation of products:

+225.3+32.6.31=1367.82 Kcal.

Compounds Ca(OH) and CaSO were supplied as saturated aqueous solutions.NaCl, KCl, acetic acid and NaNO were supplied in the form of aqueoussolutions of 0.6 N. Make-up water was supplied to the product chambersin quantities sufficient to maintain the product chamber effluents andthe electrode chamber effluents at 1.1 N. Potential 18 volts.

Source compound solutions were supplied as follows: NaCl into chamber19; CaOH into chamber 21; KCl into chamber 23; acetic acid into chamber25; NaNO into chamber 27 and CaSO into chamber 29.

After 48 hours of operation, the products were as follows: 1.1 N NaOHfrom chamber 18; 1.1 N CaCl from chamber 20; 1.1 N KOH from chamber 22;1.1 N HCl from chamber 24; 1.1 N sodium acetate from chamber 26; 1.1 NCa(NO from chamber 28 and 1.1 N H SO from chamber 30. In additionchamber 18 produced H and chamber 30 produced Test 12.-The process wasemployed to convert LiCl into several different lithium products bycombination with appropriate second source compounds. The apparatus ofFIG. 1 was modified by removing the efiluent manifolds 40, 41 andproviding individual outflow ducts.

An 0.3 N aqueous solution of LiCl was passed through deionizationchambers 21, 25 and 29. Aqueous 0.3 N solutions of sodium acetate, NaOHand NaBr were passed through deionization chambers 19, 23 and 27,respectively.

The cathode chamber etfiuent was conducted into the anode chamberthrough duct 44. Make-up water was added to the product chambers 20, 22,24, 26 and 28 and to the cathode chamber in a quantity sufiicient tomaintain the product chamber efi'luents and the efiiuent of the anodechamber at 0.8 N. Potential 14 volts.

After 48 hours of operation the product liquid of chamber was 0.8 Nlithium acetate. Chamber 24 produced 0.8 N LiOH and chamber 28 produced0.8 N LiBr. The product of chambers 22, 26 and 30 was 0.8 N NaCl.

Test 13.Principal source compound limestone CaCO Companion sourcecompound NaCl. Products CaCl and Nazcog.

Limestone was dissolved in aqueous CO solution to form C3603 and H2CO3.

HF CaCO +H CO +HF 4 NaCl=287.93 167.53 +393.44:848.90 Kcal.

for the source compounds.

HF CaCl +2HCl+HF 2X NaCO =190.7-1-79.12+541.12=810.94 Kcal.

for the product compounds.

For this test the cell was modified to reduce the thickness of thedeionization chambers to 0.5 mm. Source liquids: saturated aqueoussolution of CaCO and H CO and 0.8 N aqueous solution of the Na. Cathodechamber el'lluent passed through duct 44 into the anode chamber 30.

Make-up water was added to chambers 18, 20, 22, 24, 26 and 28 to limittheoutfiows to 1 N. Potential 26 volts.

After 48 hours of operation duct 40 yielded 1 N CaCl and HCl; ducts 41and 43 yielded 1 N Na CO With a small amount of NaHCO The productsolution of CaCl and HCl was then percolated through a bed of limestoneto form aqueous CaCl as a final product and CO gas. CO was dissolved inwater under pressure to form aqueous CO solution for dissolvinglimestone to serve as a first source liquid.

Test 14.Test 13 was repeated with an applied potential of 10 volts.After 48 hours of operation, duct 40 yielded 1 N CaCl and HCl, the HClcontent being less than in test 12, ducts 41 and 43 yielded a mixture of10 Na CO and NaHCO the NaHCO content being larger than in test 12.

Comment: The higher potential and the corresponding closer approach topolarization conditions in the relatively dilute source solution in test13 appears to be conducive to the transfer of CO anions rather than HCOanions from the deionization chambers into the concentration chambers.

Test 15.-Operation under induced polarization conditions. The membranesof the cell were modified by placing on the membrane surfaces facingchambers 21, 25 and 29 a layer of a microporous plastic material knownto the trade as Mipor 14 PN whose specification is as follows: Lowdensity polyethylene, void volume pore size range 75-125 microns withparticle retention of 10 microns, thickness 10 mils (0.010) or 0.25 mm.Cathode chamber efiluent served as anode chamber influent without theaddition of water at chamber 30.

Source solutions 0.02 N NaOH and 0.8 N NaCl. Makeup water added tochambers 18, 20, 22, 24, 26 and 28 to maintain a normality of l N at therespective outflows from chambers 20, 22, 24, 26, 28 and 30. Potential36 volts. Cell pressurized at 3 kg./cm.

After 48 hours of operation duct 40 yielded 1.0 N HCl and NaCl; ducts 41and 43 yielded 1.0 N NaOH.

Comment: The production of NaOH far exceeded the trace quantity suppliedin the first source solution. The H ions in the acid product and most ofthe OH ions in the alkaline product appear to be the result of waterdecomposition of the solvated weakly alkalized first source compoundcaused by the polarization at the membrane surfaces contacting the firstsource solution.

Test 16.A repetition of test 15 modified by supplying an aqueous 0.01 Nsolution of HCl in place of the 0.02 N NaOH.

Results: From duct 40: 1.0 N HCl; from ducts 41 and 43: 1.0 N NaOH and atrace of NaCl.

Test I7.A repetition of test 16 modified by supplying, as sourcesolutions, aqueous 0.04 N NaCl and aqueous 0.9 N NaCl. Potential 38volts.

After 48 hours of operation duct 40 yielded 1.0 N HCl and some NaCl;ducts 41 and 43 yielded 1.0 N NaOH and some NaCl.

The cell was operated under polarizing conditions of the first sourcesolution, causing decomposition of the water, so that the followingsource ions were available for transfer through the membranes: Na, Cl, Hand OH.

Test 18a.The cell was modified by substitution of neutral Mipor 13 PNmembranes 113 in place of the anion membranes of deionization chambers21, 25 and 29, the arrangement being such that the neutral membraneswould contact the adjacent cation membranes 12, thus formingdeionization chambers 21, 25 and 29 of substantially zero thickness(FIG. 4). Mipor 13 PIN membranes are low density polyethylene, voidvolume 70%, pore size range 75125 microns with particle retention of 10microns, thickness 25 mils or 1 mm.

Chambers 21, 25 and 29 received liquid only through the neutralmembranes from the adjacent product chambers. The cathode chambereffluent served as anode chamber infiuent, and rnake-up water wassupplied to chambers 18, 20, 22, 24, 26 and 28 to limit the normality ofthe effluent of chambers 20, 22, 24, 26, 28 and 30 to 0.7 N.

The membrane and chamber arrangement causes product solution fromadjacent chambers to diffuse into deionization chambers and forms thesource compound, whereupon the source compound solution is deionized inthe hereinbefore described manner. Stated briefly, product becomessource compound.

Second source solution: aqueous 0.6 N NaCl. Potential 36 volts. Cellpressurized at 3 kg./cm.

After 48 hours of operation: from duct 40: 0.7 N HCl and some NaCl; fromducts 41 and 43: 0.7 N NaOH. The

1 l first source solution consisted of the liquid in the polarized layerbetween the contacting membranes, i.e., dilute NaOH solution plussolvent decomposition products H and OH.

Text 18b.Test 18a was repeated after omission of the neutral membranesand the cell was operated at atmospheric pressure and at a potential of40 volts.

After 48 hours of operation, duct 40 yielded 0.7 N HCl and NaCl, andducts 41 and 43 yielded 0.7 N NaOH and a small quantity of NaCl.

It is apparent that the first source solution consists of the liquid inthe polarized layer at the surface of the cation membrane facing theanode, i.e., dilute NaOH solution plus decomposition products H and OH.

T est 19.Cell modified by replacing the cation membranes of chambers 21,25 and 29 by neutral Mipor l3 PN membranes, the membranes contacting theadjacent cation membranes to form deionization chambers 21, 25 and 29 ofsubstantially zero thickness.

After 48 hours of operation, duct 40 yielded 0.7 N HCl and ducts 41 and43 yielded 0.7 N NaOH and some NaCl, Again, the first source solutionconsisted of dilute HCl and decomposed Water, H and OH.

Test 20.- A cell was constructed in which chambers 21, 25 and 29 weresurface grooves in otherwise contacting Nepton anion (AR 111-A) andcation (CR6l) membranes. The grooves were 0.8 mm. wide, 0.2 mm. deep,and were spaced 10 mm. apart to form a grid pattern.

Water was supplied through these grooves from the membrane periphery.Aqueous 0.3 N NaCl solution was supplied to chambers 19, 23 and 27. Thecathode chamber efiluent was directed into the anode chamber as influent30.

Make-up water was supplied to chambers 18, 20, 22, 24, 25 and 28 tomaintain the respective efiluents at 0.8 N. Potential 36 volts.

After 48 hours of operation, duct 40 yielded 0.8 N HCl; duct 41 yielded0.8 N NaOH; duct 43 yielded 0.8 N NaOH.

Test 21.Test 20 was repeated after discontinuing the solvent inflow intochambers 21, 25 and 29. After 48 hours of operation, duct 40 yielded 0.8N HCl and a small quantity of NaCl; ducts 41 and 43 yielded 0.8 N NaOHand a small quantity of NaCl.

Test 22.-Test 20 was repeated in a cell fitted with Amfion cationmembrane C-l03 and Amfion anion membrane A-60 pairs molded together.These membranes are basically polyethylene-styrene copolymers,sulfonated and quaternized, respectively. The membranes were dried andbonded in a hydraulic press at 150 C. at a pressure of 400 lb./sq. inchto form two ply membrane structures. The bonded membranes were thenhydrolized by successive immersion in 1 N aqueous solution of HCl, NaOHand NaCl at 80 C.

The hydrolized membranes were used in place of the contacting membranesof the preceding test 21.

After 48 hours of operation, duct 40 yielded 0.8 N HCl and a smallamount of NaCl. Ducts 41 and 43 yielded 0.8 N NaOH and a small quantityof NaCl.

Test 23.In the cell of test 7 an ion conductive spacer of ion exchangematerial, substantially equally conductive to anionsand cations, wasinstalled in chambers 19, 21, 23, 25, 27, and 29 to form an ionconductive bridge between the anion and cation membranes. The cathodechamber effluent was conducted into the anode chamber. Make-up water wasadded to all product chambers and to the cathode chamber to limit thenormality of the effiuents to 0.6 N.

Water was supplied to chambers 21, 25 and 29 and an aqueous solution of0.5 N NaCl was supplied to chambers 19, 23 and 27. Potential 40 volts.

After 48 hours of operation, duct 40 yielded 0.6 N HCl and ducts 41 and43 yielded 0.6 N NaOH.

Test 24.-Test 23 was repeated after discontinuing supply of water tochambers 21, 25 and 29.

After 48 hours of operation duct 40 yielded 0.6 N HCl and a smallquantity of NaCl; ducts 41 and 43 yielded 0.6 N NaOH and a smallquantity of NaCl.

What is claimed is:

1. The process of converting, under the influence of an electriccurrent, a weakly acid compound composed of an anionic component A and acationic component C into a strong acid compound, the processcomprising,

maintaining the weakly acid compound, in solution, in

a certain deionization chamber of a multichamber electrodialysis cell inwhich the space between the electrodes is subdivided into chambers bymembranes of two kinds arranged in alternating sequence, the membranesof one kind being permeable to ions of one polarity and passageresistant to ions of the 0pposite polarity, the membranes of the otherkind being permeable to ions of said opposite polarity, the membranes ofthe two kinds being arranged in alternating order, making every otherchamber a deionization chamber and making the chambers between thedeionization chambers product chambers, there being at least threechambers of one kind and at least two chambers of the other kind;

maintaining in at least another deionization chamber spaced from saidcertain chamber a solution of a companion source compound comprising acationic component C and an anionic component A said other deionizationchamber being spaced from said certain chamber by one product chamber,said companion source compound comprising one ionic compound of acertain polarity which with an ionic component of the opposite polarityof the weakly acid compound in the adjacent deionization chamberproduces a strong acid, and said companion source compound being soselected with respect to the product compounds to be produced that thesum of the heats of formation of the'source compounds exceeds the sum ofthe heats of formation of the product compounds, one of the sourcecompounds being a .gas dissolved in liquid;

maintaining in said one product chamber a conductive liquid;

maintaining said cell under above-atmospheric pressure;

applying an electrical direct potential across said membranes andchambers and the liquids therein;

and withdrawing strongly acid product liquid from said one productchamber.

2. The process of converting, under the influence of an electriccurrent, a weak base compound composed of an anionic component A and acationic component C into a strong base compound, the processcomprising,

maintaining the weak base compound, in solution, in

a certain deionization chamber of a multichamber electrodialysis cell inwhich the space between the electrodes is subdivided into chambers bymembranes of two kinds arranged in alternating sequence, the membranesof one kind being permeable to ions of one polarity and passageresistant to ions of the opposite polarity, the membranes of the otherkind being permeable to ions of said opposite polarity, the membranes ofthe two kinds being arranged in alternating order, making every otherchamber a deionization chamber and making the chambers between thedeionization chambers product chambers, there being at least threechambers of one kind and at least two chambers of the other kind;maintaining in at least another deionization chamber spaced from saidcertain chamber a solution of a companion source compound comprising acationic component C and an anionic component A said other deionizationchamber being spaced from said certain chamber by one product chamber,said companion source compound comprising one ionic compound of acertain polarity which with an ionic component of the opposite polarityof the weak base compound in the adjacent deionization chamber producesa strong base, and said companion source compound being so selected withrespect to the product compounds to be produced that the sum of theheats of formation of the source compounds exceeds the sum of the heatsof formation of the product compounds, one of the source compounds beinga gas dissolved in liquid;

maintaining in said one product chamber a conductive liquid;

References Cited UNITED STATES PATENTS maintaining said cell underabove-atmospheric pressure;

applying an electrical direct potential across said membranes andchambers and the liquids therein;

and withdrawing strongly basic product liquid from said one productchamber.

2,815,320 12/1957 Kollsman 204180 5 2,835,632 5/1958 Kollsman 204--18O2,872,407 3/1959 Kollsman 204-301 3,084,113 4/1963 Vallino 204-18O3,086,928 4/1963 Schulz 204180 3,113,911 12/1963 Jones 204-18O 10FOREIGN PATENTS 214,772 5/ 1958 Australia. 158,405 8/ 1954 Australia.857,688 1/ 1961 Great Britain.

15 HOWARD S. WILLIAMS, Primary Examiner.

MURRAY TILLMAN, JOHN H. MACK, Examiners.

G. E. BATTIST, E. ZAGARELLA, Assistant Examiners.

1. THE PROCESS OF CONVERTING, UNDER THE INFLUENCE OF AN ELECTRICCURRENT, A WEAKLY ACID COMPOUND COMPOSED OF AN ANIONIC COMPONENT A1 ANDA CATIONIC COMPONENT C1 INTO A STRONG ACID COMPOUND, THE PROCESSCOMPRISING, MAINTAINING THE WEAKLY ACID COMPOUND, IN SOLUTION IN ACERTAIN DEIONIZATION CHAMBER OF A MULTICHAMBER ELECTRODIALYSIS CELL INWHICH THE SPACE BETWEEN THE ELECTRODES IS SUBDIVIDED INTO CHAMBERS BYMEMBRANES OF TWO KINDS ARRANGED IN ALTERNATING SEQUENCE, THE MEMBRANESOF ONE KIND BEING PERMEABLE TO IONS OF ONE POLARITY AND PASSAGERESISTANT TO IONS OF THE OPPOSITE POLARITY, THE MEMBRANES OF THE OTHERKIND BEING PERMEABLE TO IONS OF SAID OPPOSITE POLARITY, THE MEMBRANES OFTHE TWO KINDS BEING ARRANGED IN ALTERNATING ORDER, MAKING EVERY OTHERCHAMBER A DEIONIZATION CHAMBER AND MAKING THE CHAMBERS BETWEEN THEDEIONIZATION CHAMBERS PRODUCT CHAMBERS, THERE BEING AT LEAST THREECHAMBERS OF ONE KIND AND AT LEAST TWO CHAMBERS OF THE OTHER KIND;MAINTAINING IN AT LEAST ANOTHER DEIONIZATION CHAMBER SPACED FROM SAIDCERTAIN CHAMBER A SOLUTION OF A COMPANION SOURCE COMPOUND COMPRISING ACATIONIC COMPONENT C2 AND AN ANONIC COMPONENT A2, SAID OTHERDEIONIZATION CHAMBER BEING SPACED FROM SAID CERTAIN CHAMBR BY ONEPRODUCT CHAMBER, SAID COMPANION SOURCE COMPOUND COMPRISING ONE IONICCOMPOUND OF A CERTAIN POLARITY WHICH WITH AN IONIC COMPONENT OF THEOPPOSITE POLARITY OF THE WEAKLY ACID COMPOUND IN THE ADJACENTDEIONIZATION CHAMBER PRODUCES A STRONG ACID, AND SAID COMPANION SOURCECOMPOUND BEING SO SELECTED WITH RESPECT TO THE PRODUCT COMPOUNDS TO BEPRODUCED THAT THE SUM OF THE HEATS OF FORMATION OF THE SOURCE COMPOUNDSEXCEEDS THE SUM OF THE HEATS OF FORMATION OF THE PRODUCT COMPOUNDS, ONEOF THE SOURCE COMPOUNDS BEING A GAS DISSOLVED IN LIQUID; MAINTAINING INSAID ONE PRODUCT CHAMBER A CONDUCTIVE LIQUID; MAINTAINING SAID CELLUNDER ABOVE-ATMOSPHERIC PRESSURE; APPLYING AN ELECTRICAL DIRECTPOTENTIAL ACROSS SAID MEMBRANES AND CHAMBERS AND THE LIQUIDS THEREIN;AND WITHDRAWING STRONGLY ACID PRODUCT LIQUID FROM SAID ONE PRODUCTCHAMBER.